Apparatus for cooling by liquid air.



No. 666,692. Patentd lan. 29, |90I.`

' J. F. PLACE.

APPARATUS FR COOLING BY LIQUID AIR.

(Application led Aug. 17, 1900.)

3 Sheets-Sheet I.

lo Model.)

NVENTOH Patented lan. 29, 190|.

J. F, PLACE. APPARATUS F03 CUULING BY LIQUID AIR.

(Application led Aug. 17, 1900.) I v (No llodel.) 3 Sheets-Sheet 2.

/N VE N70/ W/TNESSES Patanted 1an; 29,19ol.

3 .Shams-SheetV 3.

flo; 666,692;

JFJPLAcL APPARATUS FOR GUULING BY LIIUID AIR.

(Applicltion lad Aug. 17 1990.) (no uml.)

W/ TNE SSE S d we Nonnls PETER; cn.. mum-urna. WASHINGTON. c. .f

UNITED STATES "Fries,

PATENT JAMES E. PLACE, or GLENRIDGE, NEW .iEEsEY,AssieNoR To JAMES cAvANAeH AND sAML. WEIL, 'rRUsTEEs APPARATUS FOR COOLING BY LIQUID AIR.

SPECIFICATION' forming part of Letters Patent No. 666,692, dated January 29, 1901. Application led August 1'7, 1900. Serial No. 27,119- (No model.)

To all w/wm, it m/cty concern: x

Be it known that I, JAMES F. PLACE, a citizen of the United States, and a resident of Glenridge, in the connty'of Essex and State of New Jersey, have invented certain new and useful Improvements in Apparatus for Cooling by Liquid Air, of which the following is a specification.

This invention relates to an improved apparatus for cooling any given inclosed space by means of liquid air, maintaining said space at a relatively low temperature, and regulating or controllingr said temperature automatically; and the invention relates more especially to appliances for cooling railway-cars by liquid air in connection with the air-brake system and appliances of the same.

The object of the invention is not only to cool any given inclosed space and maintain any desired low temperature therein by automatically regulating the amount of liquid air which is evaporated within a given time,

but to use in connection therewith the wellknown system of liquefying by an initial charge of liquid air a new quantity of compressed air which is supplied to the apparatus.

For this purpose my improved apparatus consists in the combination, with a suitable supply of compressed air, of a liquid-air condenser located in the space to be cooled and comprising a liquid-air reservoir adapted to receive an initial charge of liquid air, a submerged liquefying-coil in said reservoir and delivering thereto, and a counter-current apparatus whose hi gh-pressu re conduit delivers to the liquefying-coil and is connected with and fed from a source of supply of compressed air outside the compartment to be cooled from which the heat of compression has been removed by radiation or other wellknown methods and whose low-pressure conduit is connected with the liquid-air reservoir at one end and with the compartment to be cooled at the other end.

The in vention consists, next, in the combination, with an air-brake system and its accessories, of the liquid-air-condensing apparatus referred to, and, lastly, of certain details of construction and combinations of parts, which will be fully described hereinafter and finally pointed out in the claims.

In the accompanying drawings, Figure l represents a vertical transverse section of a railroad-car provided with my improved apparatus for cooling by liquid air. Fig. 2 is a side View, partly in vertical section, of that .portion of a railroad-car iitted with my air `reducing valve by which the air is supplied to the liquetier in the compartment to be cooled. Fig. 6 is an enlarged vertical section of the air-check valve by which the pressure in the compressed-air tank is retained when the brake-pipe or auxiliary air-brake reservoir is partially exhausted in the operation of putting on the air-brakes. Fig. 7 is a modification showing the air being taken from the ai r-brake auxiliary reservoir instead of from the brake-pipe,the valve and surplusreservoir being shown in section; and Fig. 8 is a plan view of the cover of the interior liquid-air reservoir,showing the holes th rough which the cold vapors are discharged by the vaporization of the liquid air.

Similar numerals of reference indicate cor- `responding parts.

Referring to the drawings, l represents the frame of an ordinary railroad-car, which is .provided at the outside and below the bottom of the same with an air-brake system or airbrake mechanism consisting of an air-brake pipe, acompressed-air brake conduit, an auxiliary compressed-air-receiver, a compressedair-supply working cylinder, brakes, levers, valves, and other appliances.

2 represents an insulating-packing, such as hair felt or tan-bark, which serves to insulate the car against the heat of the atmosphere.

3 is a casing which surrounds the liquid- IOO air reservoir 4, that is adapted to receive an initial charge of liquid-air.

5 is an insulation of hair felt or other material, which surrounds the reservoir 4 and fills up the space between the same and its casing.

6 isan air-liquefying coil, which is suspended at the inside of the reservoir 4 and which is a continuation of the high-pressure coil 7, exterior conduit 8,and air-supply pipes or conduits V9 and 10, as shown in Fig. 2. The supply-pipe 10 is connected with the compressed-air supply at the outside of the car, either with the air-brake pipe 11 or with the auxiliary air-brake reservoir 12, (shown in Figs. 3 and 4,) the pipe 10 passing from the outside through the bottom of the car to the inside thereof.

13, Figs. 1 and 2, is a tank containing calcium chlord or other moisture-absorbing substance for extracting all the moisture contained in the compressed air as it passes through the connecting-conduits 9 and 8 to the reservoir 4.

14 is a cleansing or purifying brine-tank for the purpose of removing from the compressed air all the dust, oil, or other foreign substances that are carried With it through the conduit 10 on its way to the liquid-air reservoir. These tanks or purifiers 13 and 14 are located at the inside of the car or compartment to be cooled and form a part of the liquefying and cooling apparatus.

Between the interior casing 5 and the eX- terior casing 3 of the reservoir 4 is formed an annular space 16, which is wide enough to receive the high-pressure coil or 'conduit 7. This annular' space 16 is a continuation of the dry-vapor chamber l7,formed between the cover 18 of the liquid-air reservoir 4 and the cover of the exterior casing 3. The cover 18 of the reservoir 4 has openings 19, through which the cold dry vapors of the evaporating liquid-air escape from the inside of the reservoir into the chamber 17. This cover l8 is attached to the top of the reservoir by means of clamps or clips 20 and 20 or by any other suitable means, as there is practically no pressure within the reservoir `4 to overcome. The high-pressure coil 7, which isla continuation of the conduits 10, 9, and 8, passes through the cover 18 and forms aconnection with the upper end of the liquefyingcoil 6 within the liquid-air reservoir 4. The lower end of the liquefying-coil 6 is bent inwardly and upwardly, so as to form a straight upright portion 6', which passes up Within the coil 6 and is provided with a relief-valve 21, which is held to its seat by a spring of light tension-say about fifteen to twenty pounds pressure to the square inch. dry-vapor cham ber 17 is connected freely with the lower part of the annular space 16 by 'means of a helical passage 22, which is formed between the convolutions of the highpressure coil 7. This annular space 16 is Connected at its lower part by a pipe or con- The duit 23 and 23 with perforated distributing' pipes 24, that extend around the inside of the car or compartment to be cooled, near the top of the same, said distributing-pipes discharging through perforations 25 the dry air of low temperature into the space to be cooled. The liquefying-coil k6 and the up* right pipe 6 are suspended from the cover 18 by a support 26, so that the liqnefyingcoil 6 cannot come in with the walls or bottom of the reservoir 4.

The entire apparatus is su pported on a suitable base which is insulated from the bottom of the car or compartment to be cooled.

The dry cold air that is delivered through the openings in the cover of the liquid-air reservoir into the chamber 17 is conducted from the same in a counter-current to the compressed air ascending in the high-pressure coil 7 in the helical passage or channel between the convolutions of the coil to the lower part of the annular space 16. The chamber 17 forms, with the coil 7 and the helical channel, a counter-current apparatus whose high-pressure end is connected with the liquefyingcoil and delivers into the same the compressed air fed from the air-brake system or other source of supply of compressed air in liquefied form, while its lowpressure conduit connects the liquid-air reservoir by means of the dry-air chamber and helical passage with the compartment to be cooled. The liquid air in the reservoir 4 produces, in connection with the liquefying-coil 6 and the counter-current apparatus, the liquefaction of the air supplied under pressure, which replaces continuously the initial charge of liquid air by subsequently-formed quantities of liquid air in connection with the Working of the air-brake system, so that the quantity of liquid air in the reservoir 4 is sustained by the liquefaction of a new supply of compressed air, while the evaporation of the liquid "air in the reservoir and from the same into the compartment to be cooled is kept up, so that a uniform low temperature is maintained in said compartment.

29 is a compressed-air reservoir or tank which is a part of the connectingcouduits S, 9, andvlO, but which is made of sufficient size so as to carry a surplus of compressed air to draw from and'in which the air is kept at full pressure of the air-brake or other supply, the heat of compression having been removed by radiation in passing through pipes and-connections of the air-brake system or by other well-known methods. This reservoir 29 is connected at 10 through a continuation of the conduit 10 with the air-brake pipe l1, (shown in Fig. 4,) so as to connect the airbrake pipe 11 of the car and its compressedair supply outside of the same directly with the liquid-air reservoir at the inside of the car. At 30, Figs. 2 and 4, is arranged a pressure regulating or reducing valve which forms a part of the compressedair conduit 10 and which is shown in detail in Fig. 5. Any ap- IOO IIO

proved pressure-reducing valve can he used. The one shown in Fig. 5 is made cylindrical and balanced by the annular ports 33 and 33'. As the air passes into the ports 3l and 3l at a relatively high pressure-say seventy poundsthe valve will be pressed back against its spring 32 as soon as a predetermined pressure of, say, twenty pounds is reached in that part of the conduit marked 34, so that the ports 3l and 31 are closed and the air-supply shut off. As soon as the pressure in the conduit 34 is reduced the spring forces the valve forward, so that the ports 3l and 3l are uncovered and the further-supply of compressed air is admitted. Thus the pressure of air in the conduit l0, or that part of it between the pressure regulating and reducing valve 30 and the liquid-air reservoir 4 and the liquefying-coil, is maintained at any predetermined pressure regardless of the pressure in the air-brake pipe ll or auxiliary reservoir l2 or in the surplusreservoir 2l, the reduction of pressure serving also to reduce the temperature by expansionr A modification of the construction is shown in Fig. 7, in which the compressed air for supplying the liquid-air reservoir at the inside ot' the car is taken from the compressed-air auxiliary brake-reservoir l2 (shown in Fig. 4) through the conduit l0 instead of from the brake-pipe 1l direct. The latter construction, however, as shown in Fig..4 and connected with the air-brake pipe directly, is preferred.

At 35 (shown in Figs. 3, 4, and 7 and also in Fig. 6) is arranged an ordinary check-valve for the connecting air-conduits l0', l0, 9, and 8, by which the pressure within the brakepipe ll or in the auxiliary air-brake reservoir l2 may be reduced or exhausted in operating the brake mechanism without affecting the pressure in any degree on the other side of the check-valve, or in any part of the connecting-conduit l0, 9, or 8, or inV the surplus reservoir 29, or in the coils 6 and 7, all of which parts form the compressed-air conduit by which the liquid-air reservoir at the inside is connected with the air-brake system at the outside of and beneath the car.

36 (shown in Fig. 2) is an ordinary air-cock in the compressed-air conduit, which is operated by a thermostatic governor 37 underthe action of the temperature Within the car. This thermostatic governor is made in the usual approved form and composed of two strips of metal of different degrees of contraction or expansion under the action of cold or heat, said strips being fastened together and..

bent in the shape of an arch or horseshoe. As the temperature rises the bent strip of metal expands, so as to open wider the cock 36. Vhen the temperature falls, the reverse action takes place and the cock is partially closed. Thus by admitting more or less compressed air to the coil 6 in the reservoir 4 a greater or smaller amount of liquid air is vaporized, and consequently a greater or less amount of cold dry vapor delivered to the space in the car or compartment to be cooled through the perforated pipes 23 and 24. By adjusting the clamp 38' the bent metal strip of the thermostatic governor may be set to supply to the liquid-air reservoir the required amount of compressed air in order to maintain any predetermined relatively low temperature within the car or compartment to be cooled.

As the car or compartment is comparatively air-tight, an outlet is required for permitting the dry vapors ot the liquid air to escape as they accumulate in the space to be cooled. For this purpose a number of suitable venttubes 40 are arranged in the walls of the compartment, near the top of the same, so that the vapors of higher temperature will pass out to the atmosphere. These outlet-vents are protected at the outside by ordinary flapvalves of sole-leather or other suitable material, which extend over the outer ends of the vents, so that but a trifling pressure is .required to lift them, While no air from the outside can enter the car or compartment through the Vent-tubes 40.

The operation'of my improved apparatus for cooling by liquid air is as follows: The covers of the liquid-air reservoir4 and the exterior casing of the same are removed and the reservoir is filled with an initial charge of 'liquid air. The coil 6, which is supported from the cover of the reservoir 4, is disconnected at the union 38. The covers are then replaced, connection made at the union 38, and the apparatus is ready for work. By opening the cock 39 or 39 the compressed air is at once supplied from the brake-pipe 11 or the auxiliary reservoir 12 to the connecting-conduit 10 or l0@ The air in the auxiliary reservoir l2 is kept at about seventy pounds pressure, the heat of compression being removed from the same by radiation. The compressed air passes then through the checkvalve 35 into the vreservoir 29 and through the same into the pressure-reducing valve 30, Where the pressure is reduced to the required point. It then passes through the connecting-conduits 10, 9, and 8 into the high-pressurel coil or conduit 7 of the counter-current apparatus. It passes then in an upward direction through the high-pressure coil or conduit 7 into the liquefying-coil 6, then in downward direction through the same,and through the upright pipe 6 into the liquid-air reservoir, so that the heat is quickly removed from the compressed air by the low temperature of the cold vapor and the liquid air surrounding the coils and, being under a pressure of from fifteen to twenty pounds higher than the surrounding vapors and liquid air, is quickly liquefied. The pressure-reducing valve is set so that the pressure of a little more than is required to lift the relief-valve 2l is at all times in the coil 6. Consequently the compressed air in the pipe 6 and upright IIO pipe 6' is conducted as fast as it liquees through the valve 21 in the reservoir 4 and takes the place of that which has been vaporized and passed off through the holes 19 in the cover of the reservoir into the dry-air chamber 17. As these cold dry vapors are drawn from the chamber 17 through the helical passages 22 between the convolutions of the coil 7 of the counter-current apparatus, they cool the incoming supply of compressed air in the coil as it passes up in opposite direction to the dry cold vapors and are then delivered to the upper end of the liquefyingcoil 6. By the counter-current apparatus provided ihe temperature of the incoming supply of compressed air is greatly reduced, so that it will liquefy when it enters the coil 6 in the liquid-air reservoir. The construction of the counter-current apparatus is tight and makes sure that the incoming compressed air in the cooling-coil 7 is at all times very much colder (many degrees below the freezing-point) at the top of the coil or, say, near the connection 38 than at the lower end of the coil, where it passes through the casing 3, at which it is of approximately the same temperature as the space to be cooled. The dry air-vapor as it fills the space 17 and enters the helical passage 22 between the convolutions of the coil 7 is probably about 310 below zero, whereas the compressed air as it passes through the casing 8 and enters the cooling-coil 7 is about 40 above zero. ny

moisture in the compressed air which has not been retainedby the extracting-tank 13 will liquefy and be drained back into the tank 13 before ice is formed. This is an important feature, as it is an indispensable condition precedent in liquefying air in a 'coil that it shall be absolutely free from aqueous moisture. As the compressed air passes through the conduit in the compartment to be cooled,

it passes irst to the regulating-cock 36, which is actuated by the thermostat-ic governor 37, by which more or less compressed air is admitted through the conduit to the reservoir 4, according as the temperature within the compartment to be cooled rises or falls, as hereinbefore more fully explained.

The advantages of my improved apparatus for cooling by liquid air are, first, that asupply of pure dry cold air is supplied to theA space to be cooled, so that the articles which are to be held at low temperature are always in a perfectly pure atmosphere of cold air; second, that the cooling apparatus takes up comparatively small space within the car or compartment lo be cooled, so as to leave a larger space available for the storage ot' the articles to be preserved; third, the air-brake system can be used in supplying intermittently-i. e., whenever the brakes are not required for stopping the train or in descending grades or Whenever the full power of the locomotive is not required in ascending grades for supplying compressed air to the liquefyin g coil, so that the initial charge of liquid air is kept up by the new quantity of compressed air supplied by the air-brake system, which compressed air is gradually cooled during its passage through the high-pressure and liquefying coils and delivered in liquid state to the liquid-air reservoir.

Having thus described my invention, I claim as new and desire to secure by Letters Patentl. In an apparatus for cooling by liquid air, the combination, with the compartment to be cooled, of avliquid-air condenser comprising a liquid-air reservoir adapted t-o receive an initial charge of liquid air, a submerged liquefying-coil therein and delivering thereto, and a counter current apparatus whose highpressure conduit is connected with an outside source of compressed air and with the liquefying-coil, and Whose low-pressure conduit is connected at one end with the liquidair reservoir and at the other end with coldai r-distributing pipes delivering into the compartment,substan tially as set forth.

2. In an apparatus for cooling by liquid air, the combination with the compartment to be cooled, of a liquid-air condenser comprising a liquid-air reservoir adapted to receive an initial charge of liquid air, asubmerged liquefyingvcoil therein, said liqueEying-coil delivering into said reservoir, a counter-current apparatus whose high-/pressure conduit is connected with and fed from an outside source of compressed air and delivers to the submerged coil and whose low-pressure conduit consists of a cold-air chamber above the liquid-air reservoir and a helical channel between the convolutions of the high-pressure conduit, and cold-air-distributing pipes connected with the lower end of the coldair channel and delivering into the compartment to be cooled, substantially as set forth.

3. In an apparatus for cooling by liquid air, the combination, with a compartment to be cooled, of a liquid-air reservoir adapted to receive an initial charge of liquid air, a cover for said reservoir provided with outlet-openings, a submerged liquefying-coil in said reservoir and delivering thereto, a closed exterior casing, a high-pressure coil for the incoming compressed air in the annular space between the reservoir and the exterior casing, said high-pressure coil being connected with an exterior source of compressed air, a dry-air chamber between the tops of the liquid-air reservoir and exterior casing, a pipe connection between the high-pressure coil and the submerged liquefying-coil, a helical channel formed between the convolutions of the cooling-coil and connect-ed with the dry-air chamber, and a system of air-distributing pipes connected with the lower end of said cold-air channel, substantially as set forth.

4C. In an apparatus for cooling by liquid air, the combination, with a compartment to be cooled, of a liquid-air reservoir adapted to receive an initial charge of liquid air, a submerged liquefying-coil therein and delivering IIC thereto, a valve at the outgoing end of said coil for delivering the liqueed air inio the reservoir, a cover for the liquid-air reservoir provided with outlet-openings, a closed exterior casing surrounding the liquid-air reservoir, a counter-current apparatus for the incoming compressed air consisting ot' a highpressure coil or conduit, connected with an exterior source of compressed air, a dry-air chamber above the cover of the liquid-air reservoir, and a helical channel formed between the con volutions ofthe high-pressure coil and connected Withthe dry-air chamber, a pipe connection between the high -pressure coil and the liquefying-coil, and a system of coldairdistributing pipes connected with the lower end of the helical channel, substantially as set forth.

5. In an apparatus for cooling byliquid air, the combination with the compartment to be cooled, oi a liquid-aircondenserlocated t-herein and com prisingaliquid-air reservoir adapted to receive an initial charge of liquid air, a submerged liquefying-coil therein and delivering thereto, a counter-current apparatus whose high-pressure conduit delivers to said liquifying-coil and whose low-pressure conduit is connected with the top of the liquidair reservoir and delivering to the compartment to be cooled, and a compressed-air conduit connected with the high-pressure con! d uit of said counter-current apparatus within the compartment and with the compressedair supply outside of said compartment, substantially as set forth.

6. In an apparatus forcooling by liquid air, the combination, with the compartment to be cooled, of a liquid-air condenser located there- 'in and comprising a liquid-air reservoir adapt- 'ed to receive an initial charge of liquid air, a

submerged liquefying-coil therein and delivering thereto, a counter-current apparatus Whose high-pressure conduit delivers to said liquetying-coil and whose low-pressure conduit is connected with the top of the liquidair reservoir and delivering to the compartment. to be cooled, a compressed-air conduit connected with the high-pressure conduit of lsaid counter-current apparatus Within the compartment and with the compressed-air supply outside of said compartment, and means for regulating by the temperature within said compartment the amount of air supplied to the high-pressure coil of the countercurrent apparatus from said compressed-air circuit, substantially as set forth.

7. In an apparatus forcooling by liquid air, the combination, with the compartment to be cooled, of a liquid-air condenser located therein and comprising a liquid-air reservoir adapted to receive an initial charge of liquid air, a submerged liquefying-coil therein and delivering thereto, a counter-current apparatus Whose high-pressure conduit delivers to said liquet'ying-coil and whose low-pressure conduit is connected with the top of the liquidair reservoir and delivering to the compartmentl to be cooled, a compressed-air conduit connected with the high-pressure conduit of said counter-current apparatus within the compartment and with the compressed-air supply outside of said compartment, and a thermostatic governor in the compartment to be cooled, for delivering a larger quantity of compressed air to the condenser when the temperature rises and a smaller quantity when the temperature falls in said compartment, substantially as set forth.

8. Inan apparatus for cooling by liquid air, the combination, with the compartment to be cooled,of a liquid-air condenser located therein and comprising a liq u id-air reservoir adapted to receive an initial charge of liquid air, a submerged liquefying-coil therein and delivering thereto, a counter-current apparatus Whose high-pressure conduit delivers to said liquefying-coil and whose low-pressure conduit is connected with the top of the liquidair reservoir and delivering to the compartment to be cooled, a compressed-air conduit connected with the high-pressure conduit of said counter-current apparatus within the compartment and with the compressed-air supply outside of said compartment, and valved outlet-vents near the top of the compartment for connecting the same with the outside atmosphere,substantially as setforth.

9. In an apparatus for cooling by liquid air, the combination, with an air-brake system and air-brake connections for holding and carrying compressed air for operating said system,of a liquid-air condenserlocated within the compartment to be cooled and comprising a liquid-air reservoir adapted to re.- ceive an initial charge of liquid air, a submerged liquefying-coil therein and delivering thereto, and a counter-current apparatus whose high-pressure conduit delivers to said liquefyingcoil and isfconnected with and fed from said air-brake system and whose lowpressure conduit is connected with the top of the liquid-air reservoir and delivers to the compartment to be cooled, substantially as set forth,

10. In an apparatus for cooling by liquid air, the combination, with an air-brake system and air-brake connections for holding and carrying compressed air for operating said system,of a liquid-air condenser located within the compartment to be cooled and comprising a liquid-air reservoir adapted to receive an initial charge of liquid air, a submerged liquefying-coil therein and delivering thereto, a counter-current apparatus whose high-` pressure conduit delivers to said liquefyingcoil 'and is connected with and fed from the airbrake system, and whose low-pressure conduit connects with the liquid-air reservoir, cold-air-distributing pipes connected with the low-pressure conduit,and a check-valve within said high-pressure conduit, outside of the compartment to be cooled, whereby the pressure in the air-brake system may be reduced without affecting the pressure in the highpressure conduit of the counter-current apparatus, substantially as set forth.

11. In an apparatus for cooling by liquid air, the combination, with an air-brake system and connections for holding and carrying compressed air for operating said system, of a liquid-air condenser located Within the compartment to be cooled and comprising a liquid-air reservoir adapted to receive an initial charge of liquid air, a submerged liquefying-coil therein and delivering thereto, a counter-current apparatus whose high-pressure conduit delivers to said liquefying-coil and is connected with and fed from said airbrake system, and whose low-pressure conduit connects with the liquid-air reservoir at the top and delivers to the compartment to be cooled, and a pressurereducing valve within said high-pressure conduit, whereby the compressed air supplied thereto is expanded and a uniform pressure maintained, regardless of the pressure in the air-brake system, substantially as set forth.

l2. ln an apparatus for cooling by liquid air, the combination, with an air-brake sys- Tem and connections for holding and carrying compressed air for operating said system, of a liquid-air condenser located within the compartment to be cooled and comprising a liquid-air reservoir adapted to receive an initial charge of liquid air, a submerged liquefying-coil therein and delivering thereto, a counter-current apparatus whose high-pressure conduit delivers to said liquefying-coil and is connected with and fed from said airbrake system, and Whose low-pressure conduit connects with the liquid-air reservoir at the top and delivers to the compartment to be cooledhand means for regulating by the temperature within said compartment the quantity of air supplied to said condenser from the air-brake system, substantially as set forth.

13. In an apparatus for cooling by liquid' air, the combination, with an air-brake system and connections for holding and carrying compressed air for operating said system, of a liquid-air condenser located within the compartment to be cooled and comprising a liquid-air reservoir adapted to receive an initial charge of liquid air, a submerged liquefying-coil therein and delivering thereto, a counter-current apparatus whose high-pressure conduit delivers to said liquefying-coil and is connected with and fed from said airbrake system, and whose low-pressure conduit connects with the liquid-air reservoir at the top and delivers to the compartment to be cooled, and valvedoutlet-vents connecting the compartment to be cooled near its top with the outside atmosphere, substantially as set forth.

14. In an apparatus for cooling by liquid air, the combination, Vwith an air-brake system and connections for holding and carrying com pressed air for operating said system, of a liquid-air condenser located within the compartment to be cooled and comprising a liquid-air reservoir adapted to receive an initial charge of liquid air, a submerged liquefying-coil therein and delivering thereto, an insulating casing for said liquid-air reservoir, a closed exterior casing forming an annular space between it and the interior casing, a dry-air chamber above the liquidair reservoir, a high-pressure coil located in `the annular space between the casings and connected with the submerged liquefyingcoil, a helical passage formed between the convolutions of the high pressure coiland connected at its upper end with the dry-air chamber and at its lower end with the compartment to be cooled, substantiall)7 as set forth.

15. In an apparatus for cooling by liquid air, the combination, with an air-brake sys` tem and connections for holding and carry- 'ing compressed air for operating said system,

of a liquid-airI condenser located within the compartment to be cooled and comprising a liquid-air reservoir adapted to receive an initial charge of liquid air, a submerged liquefying-coil therein and delivering thereto, a counter-current apparatus located in an annular space surrounding said reservoir and comprising a high-presen re conduit con nected at its upper end with said liquefying-coiland delivering thereto, a low-pressure conduit connected at its upper end with the liquidair reservoir and delivering at its lower end to the compartment to be cooled, a compressed-air-supply pipe connected with the lower end of the high-pressure coil of the counter-current apparatus and :with compressed-air supply outside of said compartment, and a thermostatic governor connected with the compressed-air-supply pipe at the inside of the compartment to be cooled, whereby with the rising or falling of the temperature more or less compressed air is dclivered to the condenser, substantially as set forth.

Signed at New York, in the county of New York and State of New York, this 15th day of August, A. D. 1900.

JAMES F. PLAGE.

Witnesses:

J osEPH W. DooLrr'rLE, GEORGE H. LIETER.

IOO

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